Back to Glossary

    Sites & Operations

    Principal Investigator (PI)

    A Principal Investigator (PI) is the qualified physician or other appropriately credentialed professional who has primary responsibility for the conduct of a clinical trial at an investigational site, including protocol adherence, participant safety, data integrity, and regulatory compliance.

    U.S. PIs sign FDA Form 1572 attesting to qualifications and commitments. PI obligations are detailed in 21 CFR 312.60; 312.69 and ICH E6(R3) Section 4. Sub-investigators (Sub-Is) perform protocol-specified tasks under the PI's supervision and are listed on the 1572 or delegation log.

    PI experience is a major site-selection factor; investigators with prior trials in the indication and clean inspection histories are preferred. Tools like FDA BMIS and clinical trial databases support PI vetting.

    Related terms

    See how Kitsa applies this in your trials

    Kitsa's agentic AI compresses protocol development, site selection, and patient pre-screening from months into weeks.

    Request a demo